The present invention builds on the task (1) to reduce in the case of coating installations, for example with virtually continuous 24-hour production operation, the shutdown times for maintenance, such as, for example, for replacing material sources consumed during the coating process or other installation parts such as coating masks. Therein (2) the coating installation should be constructionally as simple and compact as feasible.
Coating installations conventionally comprise a transport chamber, wherein, in the simplest case, workpieces are transported from an input/output lock station to a coating station. They are therein coated and subsequently transported back to the input/output lock station. Based on the requirement (2) for the simplest possible concept, a pump unit is provided via a pump opening on the transport chamber, which simultaneously handles the evacuation of the treatment station. Thus, in installations of this type the transport chamber is also flooded during the flooding of the treatment station. Otherwise the coating station would need to be compartmentalizable with respect to the transport chamber by employing a relatively complicated valve device.
A critical extension of the production shutdown times during the flooding of coating station and transport chamber results therefrom that, together with the transport chamber, at least portions of the pump unit flanged onto the pump opening are flooded. This leads, for one, to relatively long reconditioning times for the resumption of operation. For another, when, for example, turbovacuum pumps are provided on the pump unit, the latter would have to be compartmentalized against the flooding, which requires complicated and expensive compartmentalization valves.
The above cited task (1), namely minimizing shutdown times simultaneously with generating (2) as simple as feasible an installation configuration with high production rate, is realized through an installation according to the wording of claim 1.
Consequently, the coating installation according to the invention comprises a transport chamber with a workpiece transport configuration. The latter has at least two transport rams connected with a rotational axle driven under control, with transport rams, driven under control, which can be linearly extended and retracted. The transport rams are therein in the shell line of one and the same rotation body about the rotational axis and are, with respect to a given direction on the rotational axis, extendable and retractable in the same direction. Each ram bears at the end a workpiece receiver. On the transport chamber are furthermore provided at least two operating openings via which the transport chamber communicates with stations, of which one is a coating station. The surface normals of the clearance areas of said operating openings are therein oriented in the direction of shell lines of the rotation body.
Further provided on the coating installation according to the invention is a pump unit, communicating with the transport chamber via a pump opening, which is effective for the transport chamber as well as also for the coating station.
At least one of said rams has at the end a closure configuration or can be equipped therewith. In order to optimize the simple installation concept which, in all implementations of the coating installation according to the invention, permits extremely high production rates, also with respect to necessary production interruptions in connection with flooding, while maintaining the simple constructional concept, the pump opening is disposed on the chamber such that said ram can be oriented toward the pump opening, wherein the closure configuration, with orientation of said ram toward the pump opening and subsequently its moving, enters with the pump opening into an operational connection forming a sealed closure.
With respect to the fundamental structure of the transport chamber with said rams, reference is made in particular to EP 0 518 109 corresponding to U.S. Pat. No. 5,245,736 and to DE-GM 29 716 440 corresponding to U.S. Pat. No. 6,416,640.
In a first embodiment of the coating installation according to the invention the rotation body is a cylinder or a cone with an angle of aperture less than 90xc2x0, and said rams, correspondingly, can be extended and retracted under linear driving parallel or at an obtuse angle with respect to the rotational axis.
But in a preferred embodiment the rotation body is a special case of a cone, namely with a 90xc2x0 aperture angle xcfx86, and the rams project radially from the rotational axis. The operating openings and the pump opening comprise therein surface normals which are in the rotational plane of the rams about the rotational axis.
Consequently, in the last mentioned, preferred embodiment the workpiece transport configuration has at least two transport rams projecting radially from a rotational axle driven under control and linearly extendable and retractable driven under control, which thus are in a plane perpendicular to the rotational axis. Again, at the end on each ram are provided corresponding workpiece receivers. Furthermore, in addition, at least two operating openings, now disposed with the surface normals of the clearance openings in said plane, are provided on the transport chamber, via which the latter communicates with stations, of which, furthermore, one is a workpiece coating station. As in all embodiments of the coating installation according to the invention, here also a pump unit is provided which, effective for the transport chamber as well as also for the coating station, communicates via a pump opening with the transport chamber.
As stated, the pump opening is disposed on the transport chamber such that at least one of said rams, preferably each, can be oriented toward it. At least one of said rams comprises the closure configuration or can be equipped therewith such that, with the orientation toward the pump opening by being moved, can here also enter with the pump opening into an operational connection forming a sealed closure.
If, in the preferred embodiment of the coating installation according to the invention, and with respect to the rotational axis, the rams are directed radially, the surface normal of the clearance area of the pump opening is consequently also disposed in the rotational plane of said rams.
While it is in principle known from DE 19 742 923 to close the pump opening to one pump unit for flooding a transport chamber, the transport chamber provided on the installation known therefrom, however, comprises as a workpiece transport configuration a solid carrier plate driven about a rotational axis, on whose one plate side, peripheral with respect to the rotational axis, the workpieces are positioned. By axial raising or lowering of the carrier plate, all workpieces, given the corresponding rotational angle orientation, are simultaneously moved toward or moved away with respect to the stations flanged onto the corresponding front face of the transport chamber wall. The plate surface opposing the transport surface of the carrier plate in the case of flooding of the transport chamber, acts onto a pump opening such that it closes it. This pump opening is disposed on the front face, with the front face of the transport chamber opposing the stations. This installation meets none of the requirements according to the task made of the installation according to the invention. For example it is evident:
the lifting mechanism for the transport plate must be layed out such that in production it can not only supply the stations with workpieces, but, in the much rarer case, can also be retracted again for the purpose of closing the pump opening: the entire installation must be developed especially for this xe2x80x9crarexe2x80x9d case alone.
Since this additional lift can only be minimized within limits, namely to the extent that the pump effect is not to be choked through the transport plate in production position, this leads to structural enlargement and further complication of the overall installation.
Relatively complex and expensive measures must be taken to develop the carrier plate, which is locally heat loaded due to the working, such that tight closing of the pump opening can be accomplished at any time and independently of the rotational position.
The transport plate, which, for the reason stated, must occasionally be at relatively high mass, counteracts high production rates in so far as during the incremental rotation of this plate high inertial moments must be overcome, which requires correspondingly expensive drives for high production rates.
In a highly preferred embodiment of the coating installation according to the invention only two of the rams are provided which are disposed in said plane offset by 180xc2x0 with respect to the rotational axis.
If the rotation body is a cylinder or a cone with an aperture angle less than 90xc2x0, said only two rams are disposed in a plane containing said rotational axis. In the case of the preferred embodiment, in which the rotation body is degenerated into a cone with an aperture angle of 90xc2x0, said provided two rams are disposed opposite with respect to the rotational axis and, in top view onto the rotational axis, offset by 180xc2x0, consequently also in said plane containing the rotational axis.
In any event, through the two-ram embodiment optimally deep masses to be moved with the transport configuration are realized, and it was found that the minimization of these masses, in view of the acceleration behavior of a rotation stepping drive provided for the transport configuration, is significantly more effective than a concept with more than two rams and a corresponding increase of the number of provided coating stations. Through this preferred embodiment, consequently, simultaneously with critical simplification of the installation within the scope of the task of the invention (2), optimization of productivity is attained. This is accomplished through the option of realizing the transport between the provided stations through rapid 180xc2x0 rotational angle steps.
In a highly preferred manner therein are also provided only two of the stations, of which the one is a lock station and the two operating openingsxe2x80x94to the lock station and to the coating stationxe2x80x94are offset by 180xc2x0 with respect to the rotational axis of the workpiece transport configuration.
If, as in the one of the preferred embodiments of the installation according to the invention, the rotation body is a cylinder or a cone with an aperture angle less than 90xc2x0, said operating openings are disposed such that the surface normals of its clearance openings are aligned with shell lines of said rotation body and specifically with shell lines which oppose one another offset by 180xc2x0 with respect to the rotational axis, i.e. they lie in a plane which contains the rotational axis.
In the especially preferred embodiment of the installation according to the invention, in which the rotation body is degenerated to a cone with an aperture angle of 90xc2x0, said operating openings viewed in the direction of the rotational axis and, with respect to it, are disposed oppositely with radially directed surface normals.
In a preferred further development of the last cited embodiment, the pump opening between the operating openings and, with respect to them, is disposed preferably offset by 90xc2x0.
Consequently, in the one preferred embodiment of the installation according to the invention, in which the rotation body is a cylinder or a cone with an aperture angle less than 90xc2x0, the pump opening is again disposed such that its surface normal is aligned with shell lines of the corresponding rotation body, and it is preferably, viewed in the direction of the rotational axis offset by 90xc2x0 with respect to the operating openings, disposed inbetween.
In the especially preferred embodiment the latter applies identically: in view onto the rotational axis, the surface normals, which are now directed radially, of the operating openings appear to be opposite offset by an angle of 180xc2x0 with the pump opening offset with respect to it by 90xc2x0 and disposed in-between.
Therewith, on the one hand, it is achieved that in production operation the pump effect is not impaired by the workpiece transport configuration; on the other hand, for the case of flooding through corresponding driving of the rotational drive alone for the workpiece transport configuration, a 90xc2x0 xe2x80x94instead of 180xc2x0 xe2x80x94rotational angle step can be initiated in order to bring one of the provided rams into an orientation toward the pump opening. Through the extension and retraction of the rams, provided in any event also for the production, the pump opening is closed or again released. Consequently, this does not require additional expenditures, since the ram under consideration carries out said pump opening-related lift also during the production with respect to the operating opening.
It is therein further preferred to dispose a supplemental opening in the wall of the transport chamber opposite, with respect to the rotational axis, to the pump opening such that in the plane, preferably each offset by 90xc2x0, four openings are provided. This supplemental opening can be employed for a multiplicity of different purposes. It can, for example, together with the closure of the pump opening, if required, also be closed, it can, when not in use, be closed with a cover, and, for example, be employed for service work of every type and/or for measuring workpiece parameters, such as for example for measuring coating distributions and/or coating thicknesses, etc.
Within the scope of as simple as feasible an installation concept (2), it is further preferably proposed that the interior volumes of the coating station and of the transport chamber are connected via a communication connection, not under control, i.e. without a controllable valve configuration being provided in such a connection. Consequently such a connection, as will yet be explained, is an uncontrolled bypass connection.
In a further highly preferred embodiment of the installation according to the invention the coating station provided is a sputter station.
Even though the closure configuration provided at the ends of the rams of the coating installation according to the invention can also be formed by disk-form workpieces themselves positioned thereon or by other members especially provided for this purpose, a further simplified concept is attained thereby that the workpiece receivers are formed by workpiece receiving plates, in each instance for at least one disk-form workpiece, and that this plate forms the closure configuration. In principle, on the provided workpiece receivers in each instance one disk-form, especially preferred circular disk-form workpiece, can be applicable so as to be centered with respect to the ram axis, or, grouped about said ram axis two or more disk-form workpieces, again clearly preferably circular disk-form workpieces.
Although it is further quite possible to provide on the coating installation according to the invention only one or only a portion of the provided ram with the required closure configurationxe2x80x94to orient the particular ram in the case of flooding toward the pump openingxe2x80x94in a highly preferred embodiment on all rams said closure configuration is provided and this, as stated, preferably also developed as a workpiece carrier plate. But therewith simultaneously the option is given of closing also the operating openings in production operationxe2x80x94as in flooding operation, the pump opening. If a lock station is provided, in this case said closure configuration on the ram oriented to the lock station acts directly as a lock valve and/or on the coating station said closure configuration of the ram, correspondingly oriented toward this station, separates the coating process from the transport chamber.
The installation according to the invention, in particular in its preferred two-ram/two station configuration, is in particular suitable for the fabrication of magnetic or optic storage disks, preferably optic storage disks, therein in particular for the fabrication of CDs of all types, be these normal factory-recorded CDs, CDRs or CDRWs.